I am working on a project at a company am interning as a manufacturing engineer and the project is basically using cameras to record an assembly line. The tough part is I want this system to be mobile so we can use it on multiple assembly lines and some assembly lines have very limited outlets. The IT department here recommended using Wi-Fi cameras and our senior network architect tried using an Old D-Link camera on a NAS he had at home and it worked. I am having issues finding a Wi-Fi that operates on a built-in battery or a camera that can be powered through a power bank, am not sure if anyone here tried with one but if anyone has any advice I will really appreciate it.

Also this system would not be recording 24/7, the idea is to record the line for a couple of hours and send all the recordings to a NAS and then we could collect all the data from the recordings.

This is really not a surveillance question but not sure where else I could post it. Thanks

You haven't really specified the required camera characteristics, apart from the requirement for battery operation.
It does seem that you will be reviewing stored recordings, so my suggestion would be :

Use a cycling helmet camera, that will record to an SD card, and have a two hour battery life.
The SD card can be removed to process the resultant recordings.
If longer run-time is needed - use an external battery bank to supplement it.

This would be a low-cost, and maybe effective solution, unless you are looking for a UHD video stream.

TS-431+ as primary storage and media server and a bunch of IP cams under Surveillance Station.

For Camera characteristics, there is not really much that is required.
-Something that records at 720p, a higher resolution would be nice but not required
-Viewing angle of 90-120
-Cloud Storage

About the SD cards, our IT department does not really want to use SD cards as a primary storage device since it can be stolen or switched out so they would just refuse that. Another reason for having a NAS is because multiple people are going to be reviewing the footage to collect data and stuff. We would also like to store the recordings for reference and IT would like to have separate storage for all that. Thanks for the help.